1. Field of Invention
The present invention relates to a polishing pad and the method thereof. More particularly, the present invention relates to a polishing pad with high rigidity and high compressibility utilized in Chemical Mechanical Polish (CMP).
2. Description of Related Art
Chemical Mechanical Polishing (CMP) is a process that is used to flatten the semiconductor wafers. CMP takes advantage of the synergetic effect of both physical and chemical forces for polishing of wafers and applies a load force on the back of a wafer while it rests on a polishing pad. Both the polishing pad and wafer are then counter rotated while a slurry containing both abrasives and reactive chemicals passes underneath. CMP is an effective way for uniformly flatting the entire substrate.
The goal of CMP is to uniformly flatten the entire wafer and reproduce the flatness on wafers. Wafer flatness depends on the rigidity and the compressibility of the polishing pad. For example, a high-rigidity polishing pad may increase the flatness of the wafers, and a high-compressibility polishing pad may increase the uniformity of the wafers. As a result, a high-compressibility polishing pad may be used after a high-rigidity polishing pad to increase the uniformity of the wafers, and that may spend more time and reduce the productivity of the wafers. The material of the known polishing pad is difficult to balance rigidity and compressibility.
For the forgoing reasons, there is a need for a polishing pad having desired rigidity and compressibility.